func (this *BWTBlockCodec) createGST(blockSize uint) (kanzi.ByteTransform, error) {
// SBRT can perform MTFT but the dedicated class is faster
if this.mode == GST_MODE_RAW {
return nil, nil
}
if this.mode == GST_MODE_MTF {
return transform.NewMTFT(blockSize)
}
return transform.NewSBRT(this.mode, blockSize)
}
func main() {
fmt.Printf("\nCorrectness test")
for ii := 0; ii < 20; ii++ {
rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
var input []byte
if ii == 0 {
input = []byte{5, 2, 4, 7, 0, 0, 7, 1, 7}
} else {
input = make([]byte, 32)
for i := 0; i < len(input); i++ {
input[i] = byte(65 + rnd.Intn(5*ii))
}
}
size := len(input)
mtft, _ := transform.NewMTFT(uint(size))
transform := make([]byte, size+20)
reverse := make([]byte, size)
fmt.Printf("\nTest %d", (ii + 1))
fmt.Printf("\nInput : ")
for i := 0; i < len(input); i++ {
fmt.Printf("%d ", input[i])
}
start := (ii & 1) * ii
mtft.Forward(input, transform[start:])
fmt.Printf("\nTransform : ")
for i := start; i < start+len(input); i++ {
fmt.Printf("%d ", transform[i])
}
mtft.Inverse(transform[start:], reverse)
fmt.Printf("\nReverse : ")
for i := 0; i < len(input); i++ {
fmt.Printf("%d ", reverse[i])
}
fmt.Printf("\n")
ok := true
for i := 0; i < len(input); i++ {
if reverse[i] != input[i] {
ok = false
break
}
}
if ok == true {
fmt.Printf("Identical\n")
} else {
fmt.Printf("Different\n")
}
}
// Speed Test
iter := 20000
size := 10000
fmt.Printf("\n\nSpeed test")
fmt.Printf("\nIterations: %v", iter)
for jj := 0; jj < 4; jj++ {
input := make([]byte, size)
output := make([]byte, size)
reverse := make([]byte, size)
mtft, _ := transform.NewMTFT(uint(size))
delta1 := int64(0)
delta2 := int64(0)
if jj == 0 {
fmt.Printf("\n\nPurely random input")
}
if jj == 2 {
fmt.Printf("\n\nSemi random input")
}
for ii := 0; ii < iter; ii++ {
for i := 0; i < len(input); i++ {
n := 128
if jj < 2 {
// Pure random
input[i] = byte(rand.Intn(256))
} else {
// Semi random (a bit more realistic input)
rng := 5
if i&7 == 0 {
rng = 128
}
p := (rand.Intn(rng) - rng/2 + n) & 0xFF
input[i] = byte(p)
n = p
}
}
before := time.Now()
mtft.Forward(input, output)
after := time.Now()
delta1 += after.Sub(before).Nanoseconds()
before = time.Now()
mtft.Inverse(output, reverse)
after = time.Now()
delta2 += after.Sub(before).Nanoseconds()
}
idx := -1
// Sanity check
for i := range input {
if input[i] != reverse[i] {
idx = i
break
}
}
if idx >= 0 {
fmt.Printf("Failure at index %v (%v <-> %v)\n", idx, input[idx], reverse[idx])
os.Exit(1)
}
fmt.Printf("\nMTFT Forward transform [ms]: %v", delta1/1000000)
fmt.Printf("\nThroughput [KB/s]: %d", (int64(iter*size))*1000000/delta1*1000/1024)
fmt.Printf("\nMTFT Reverse transform [ms]: %v", delta2/1000000)
fmt.Printf("\nThroughput [KB/s]: %d", (int64(iter*size))*1000000/delta2*1000/1024)
println()
}
}
